Liquid fuel combustion system



P 1951 I 0. N. LAWRENCE ET AL 2,566,734

LIQUID FUEL COMBUSTION SYSTEM Filed Nov. 13, 1947 Lzjueflrbol s 0- ZYLQ, wi 612, (/8

Patented Sept. 4, 1951 LIQUID FUEL COMBUSTION SYSTEM Owen Napier Lawrence and Eugene Harold Warne, Birmingham, England, assignors to Joseph Lucas Limited, Birmingham, England Application November 13, 1947, Serial No. 785,730 In Great Britain October 25, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires October 25, 1966 2 Claims.

This invention relates to liquid fuel combustion systems for use in association with the combustion chambers of prime movers, or other purposes, and of the kind in which the fuel is discharged through a plurality of nozzles of the swirl type, these being supplied by a pump. To ensure adequate swirling f the liquid fuel emerging from a swirl-type nozzle it is necessary for the quantity of liquid fuel supplied to the nozzle to be in excess of the quantity discharged by the nozzle under at least lowor medium-load conditions of the prime mover, and provision is made for enabling the excess liquid fuel received by the nozzle to enter a return flow pipe instead of emerging from the nozzle outlet. When the system employs a number of nozzles it is required that the discharge from all shall be equal, but variations in the return flows due to accidental conditions, such as variations in the relative resistances of the return-flow pipes, makes this requirement difficult to attain.

The object of the present invention is to enable, in a simple and convenient manner, equality to be obtained in all the return flows, thus ensuring equality of discharge from all the nozzles.

The accompanying drawing represents diagrammatically one embodiment of the invention for use in a fuel supply system for the combustion chamber of a jet propulsion prime mover, gas turbine, or the like.

Referring to the drawing, we employ a plurality of pumps a of the gear type. These are contained in a common housing b and are interconnected so that all are operated at the same rate. Also they are connected to a common drivingmotor c.

The motor consists of a liquid-operable motor, which may be of the gear type, adapted to be driven by the liquid fuel supplied to swirl-type discharge nozzles h from a supply pump (1. To ensure adequate swirling of the fuel emerging from the nozzles 11., the quantity of liquid fuel supplied'by the pump d to the nozzles is in excess of the quantity discharged by the nozzles under at least low-or mediumload conditions of the prime mover, gas turbine, or the like.

The inlets e of the pumps a are respectively connected to the discharge nozzles 71. by separate return pipes I through which the excess liquid fuel supplied to the nozzles can flow. The pumps a and motor 0 discharge into a common passage 1' which is connected by a supply pipe 7 to the nozzles h. Under full-or heavyload conditions of the prime mover, gas turbine, or the like, the quantity of liquid fuel emerging from the nozzles h is in excess of that necessary to ensure adequate swirling of the emerging fuel. Consequently, in these conditions the proportion of fuel flowing through the return pipes I from the nozzles can be reduced, and to this end, we may combine with the system means for automatically reducing the rate of action of the motor 0 and associated pumps a under the said conditions. This provision is conveniently made by connecting a bypass lc across the inlet and outlet of the motor c and arranging in the by-pass a valve 111. loaded by a spring n and responsive to the liquid pressure at the inlet side of the motor. Until a predetermined pressure is reached the valve remains closed. Subsequently the valve opens, causing the motor to be by-passed, thereby reducing the rate of action of the motor to an extent dependent on the amount of opening of the valve.

The supply pump d shown in the diagram is of the swash plate type having an angularly adjustable swash plate 0 for varying the output of this pump, the swash plate being movable by fluid pressure acting on a spring-loaded piston q, in response to an automatic control means r through which the output of the pump is conveyed to the motor 0 and nozzles h, but the pump d and the said means 1' form no part of the present invention.

By this invention we are able in a convenient and satisfactory manner to ensure equality of return flow from all the nozzles and thereby obtain uniformity of discharge at the nozzles.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A liquid fuel supply system comprising in combination a main liquid fuel supply pump, a plurality of swirl-type nozzles, a passageway interconnecting the pump and nozzles so that liquid fuel in excess of the quantity to be discharged by the nozzles can be supplied thereto by the pump, return flow passages corresponding in number and respectively connected to the nozzles so that the excess liquid fuel supplied to the nozzles can flow into the return flow passages, secondary pumps corresponding in number to and respectively situated in the return flow passages, a motor arranged in and operable by liquid fuel flowing through the passageway interconnecting the main liquid fuel supply pump and the nozzles, and means interconnecting the secondary pumps and motor so that the latter serves to drive all of the secondary pumps at the same rate.

2. A liquid fuel supply system as claimed in claim 1, in which the motor has associated therewith a. by-pass provided with flow controllin 4' UNITED STATES PATENTS means responsive to the pressure of the liquid Number 1 Name Date m1 delivered by the'main p m r varying the 1,628,424 Peabody May 10, 1927 rate oLaction of the mo r and the Secondary 2,127,172 Hermitte Aug. 1a, 1938 pumps. 2,263,913 Bargeboer Nov. 25, 1941 OWEN NAPIER LAWRENCE 2,290,350 Olches July 21, 1942 EUGENE HAROLD 2,334,679 Mason et a1. Nov. 16, 1943 FOREIGN PATENTS Country Date Germany Jan. 30, 1922 REFERENCES CITED The following references are of record in the 10 Number file 0! this patent: 348,108 

